The present innovation relates to a novel formulation capable of increasing the amount of stem cells and progenitor cells in circulation in the peripheral blood of a mammal; the formulation is characterized in that it contains defibrotide in combination with at least one haematopoietic factor having the capacity to mobilize haematopoietic progenitors, preferably G-CSF. In one embodiment, the formulation includes two separately administrable formulations, one containing a haematopoietic factor having the capacity to mobilize haematopoietic progenitors and the other containing defibrotide. The formulation is effective to achieve an increase in the number of haematopoietic progenitor cells that is greater than an increase in the number of haematopoietic progenitor cells achieved by the haematopoietic factor alone.